Two groups of microwave type U and RS bursts on 15 February 2011

Two groups of microwave type U and reverse-slope (RS) bursts after the soft X-ray (SXR) maximum were observed with the 2.6-3.8 GHz spectrometer of Chinese Solar Broadband Radio Spectrometers (SBRS/Huairou) on 15 February 2011. On that day, an X2.2 solar flare occurred in the active region (AR) NOAA 11158. We utilized a shear-driven quadrupolar reconnection (SQR) model to analyze the observed type U and RS bursts and found that the two loops involved are basically in the same spatial scale and have a height difference of about 1300 km. We interpreted these bursts to be a result of a new reconnection process between the two loops.